[WALLET] Addition of ImmatureCreditCached to MarkDirty()

To protect against possible invalidation and to bring conformity to the code.

Author: spencerlievens

src/wallet/wallet.h

@@ -361,6 +361,7 @@ class CWalletTx : public CMerkleTx
     {
         fCreditCached = false;
         fAvailableCreditCached = false;
+        fImmatureCreditCached = false;
         fWatchDebitCached = false;
         fWatchCreditCached = false;
         fAvailableWatchCreditCached = false;